diff -r 000000000000 -r 6474c204b198 ipc/glue/SharedMemory_posix.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ipc/glue/SharedMemory_posix.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,38 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <sys/mman.h>         // mprotect
+#include <unistd.h>           // sysconf
+
+#include "mozilla/ipc/SharedMemory.h"
+
+namespace mozilla {
+namespace ipc {
+
+void
+SharedMemory::SystemProtect(char* aAddr, size_t aSize, int aRights)
+{
+  int flags = 0;
+  if (aRights & RightsRead)
+    flags |= PROT_READ;
+  if (aRights & RightsWrite)
+    flags |= PROT_WRITE;
+  if (RightsNone == aRights)
+    flags = PROT_NONE;
+
+  if (0 < mprotect(aAddr, aSize, flags))
+    NS_RUNTIMEABORT("can't mprotect()");
+}
+
+size_t
+SharedMemory::SystemPageSize()
+{
+  return sysconf(_SC_PAGESIZE);
+}
+
+} // namespace ipc
+} // namespace mozilla